Stranding machine arrangement



United States Patent 2,873,569 a STRANDING MACHINE ARRANGEMENT r Hans-Werner Schinke, Rheinhausen, and Helmut Otto Lutcke, Dusseldorf-Ratingen, Germany, nssignors to Aktiengesellschaft fuer Unternehmungen der Eisenund Stahlindustrle, Essen, Germany l Application November 2a, 1956, Serial No. 624,837 Claims priority, application Germany December 6, 1955- 6 Claims. (Cl. 51-5832) V p The present invention relates to stranding machines, particularly, for manufacturing electric cables. 1

, stranding machines have been known in which the bobbin cradles are turned in reverse'direction during the rotation of a rotating body in whichthese cradles are mounted. Generally, a reverse rotationof 360 is used,

whereby the bobbin cradles retain their position in space, so that the workpiece or cable is stranded without twisting. However, in many cases, it is desirable to subject the workpiece or cable, i. e., the strands, wires, conductors, etc., to be stranded, to a reverse rotation which is larger or smaller than 360". Gears with adjustable transmission ratio built in the driving mechanism have been used for this purpose.

It is an object of the present invention to provide a stranding machine in which the reverse rotation of the bobbin cradles is obtained without gears being inserted between the driving mechanism of the stranding machine and the bobbin cradles. This has the great advantage of avoiding backlash always present in gears, such backlash resulting in inaccuracies in the reverse rotation and, thereby, in the relative position of the wires or conductors within the cable. Furthermore, the omission of the gears as such is an advantage in the design of the new stranding machine.

It is another object of the present invention to provide a stranding machine in which the bobbin cradles are driven individually or in groups by an electromotor, the housing of which is mounted on the rotating body-of the stranding machine, while the rotor of the electromotor is associated with the bobbin cradle and while the cradle motors are electrically connected in synchronism to the driving motor of the rotating body, i. e., to the main driving motor.

It is a further object of this invention to provide a tacho-dynamometer for the main driving motor and for each of the bobbin cradle motors and to interconnect-said tacho-dynamometers by means of a control unit which is manually controllable with the aid of potentiometers. By this or similar circuit arrangements, such as frequency control circuits, it is possible to act rapidly on the reverse rotation drive means of the bobbin cradles in positive or negative direction if a correction of the instantaneous position of a bobbin cradle should be necessary. I It is a still further object of the present invention to insert a transmission gear between the bobbin cradle and the bobbin cradle motor, whereby said transmission gear is designed in such a manner, that any undesirable turning of the bobbin cradle is prevented when the bobbin cradle motor does not carry current. For example, a worm gear, a shifting armature motor, a magnetic clutch or another suitable device or brake may be used for this purpose.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific ice examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

In the drawings:

Figure 1 shows schematically a side view, partially in section, of a first embodiment of a high speed stranding machine according to the invention with its electric control circuit diagram;

Figure 2 is a second embodiment and illustrates schematically in the same way as Figure 1 a stranding machine of the basket type.

In the high-speed stranding machine according to Figure 1, a rotating body 1 is rotated by means ofa main driving motor 2 via a train of gears 3, 4 and 5. A number of bobbin cradles 6 with bobbins 7 are arranged on a common axis one behind the other within the rotating body 1 in a manner known per se. Each of the bobbin cradles 6 is driven by a cradle motor 8, the housing of which is mounted on the rotating body 1 while its rotor is operatively connected to the bobbin cradle 6. Instead of this, it is possible to mount the housing of the cradle motor on the bobbin cradle and the rotor of the cradle motor on the rotating body. In order to retain the proper position of the bobbin cradles in space, the latter have to be turned in reverse direction 360 during each revolution of the rotating body 1. This is obtained by providing the main driving motor 2, as well as each of the bobbin cradle motors 8, with tachodynamometers 9 and 10, respectively. While these tachodynamometers rotate, they supply a control current to an electric control unit 11, in which the measured value of the number of revolutions given by this control current is compared with a rated or fixed value. As a result of this, a control impulse is obtained by means of which the number of revolutions is kept constant. The control unit 11 can be manually adjusted by means of a potentiometer 12 to change the rated value of the number of revolutions for each of the bobbin cradle motors 8, whereby the reverse rotation of each of the bobbin cradles 6 can be varied in positive or negative direction. The bobbin cradle motors 8 and their tacho'dynamometers 10 are connected to the control unit 11 in the usual manner via circuit means including slip rings 13 and 14 and brushes 15 and 16, respectively, engaging these slip rings. Transmission gears 17 may be inserted between the rotors of the bobbin cradle motors 8 and the bobbin cradles 6, said transmission gears being equipped with a known brake or a self-locking device (not shown), such as a worm gear, to prevent unintended rotation of the bobbin cradle 6.

In the basket-type stranding machine according to Figure 2, the rotating body 13 is driven by means of a main driving motor 21 with the aid of gears 19 and 20.

bobbin cradles 22 with their bobbins 23 are mounted.

Each of the bobbin cradles 22 is driven by a cradle motor 24, the housing of which is secured to the stranding basket 18, and the rotor of which is connected to the bobbin cradle 22. The main driving motor 21 is provided with a tacho-dynamometer 25 and each bobbin cradle motor 24 has its own tacho-dynamometer 26 in order to turn the bobbin cradles 22 in reverse direction. The tachmdynamometcrs 25 and 26 cooperate via an electric control unit 27 to maintain constant the number of revolutions in principally the same manner as it has been explained in connection with the embodiment of Figure l. The adjustable potentiometer for determining the rated value of the number of revolutions is denoted by 28.

Any other suitable electric device, such as a frequency control circuit, an electric shaft arrangement, or the like,

maybe employed 'in'p lace'of the control system described in the foregoing.

In many instances, it will be sufiicient to provide in high speed stranding machines acommon driving motor for several bobbin cradles.

We claim:

' 1. In a stranding machine for stranding cables and the 1ike' froma"plurality'of individual strands, a rotating body, a plurality of bobbins corresponding substantially to the number of strands to be used,'c'radle means supportingsaid bobbins' and. rotatably mounted in said rotatingbody, respective drive means for said rotating body and said cradle means; separate tacho-dynamometer means associated with each of said respective drive means, an-electric control'unit in circuit witlr'said tach -dynamometer means and said respectivedrivemeans,"whereby a rated valtie to thereby indicate the speedratio between the rotating-body and'the bobbins.

- 2. lna stranding machine according to 'clainil, wherein 'said rotating body is constructed to define a stranding basket for said bobbins. v

=3; ln a machine arrangement" according to -claim l,

wherein said driven ieans for said cradle means is provided -with-'a-relatively stationary housing and a rotor rotating therein, said housings being mounted on said rotating body and each of said rotors being operatively connected to one of said cradles.

4. In a machine arrangement for stranding cables according to claim 1, wherein a transmission gear is provided b'ctweemea'ch 'of "said cradles-and its associated drive means; and wherein a braking'means is operatively .connected'witheach of said'transmission gears.

' 5. In amachine' arrangement for stranding cables according to claim 1;:wherein a transmission gear is pro vided. between each of said cradles and each of said elcctronioto'rs,"'andwherein a" self-locking means is operatively connectedwitlr each of said transmission gears.

6. In a machine arrangement for stranding cables according to claim lfwlier'ein said electric control unit is adapted to individually vary the speedof said respective drive' means. 

